The present disclosure relates to a sorting apparatus and a sorting method for sorting particles of cells and the like using a dielectrophoretic force.
From the past, as a method of sorting particles in a fluid by an electromagnetic force, there are the following two methods, for example. One is a method of performing an electrophoresis of charge particles by forming a DC electric field in a flow channel. The other is a method of performing an electrophoresis of particles while depending on a complex permittivity of a medium and particles by forming a DC or AC electric field in a flow channel and giving a spatial heterogeneity, that is, an electric field intensity gradient to the electric field. As an example of the latter method of performing an electrophoresis, there is a cell sorting apparatus (cell analysis/sorting system) disclosed in Japanese Patent Application Laid-open No. 2012-98075 (hereinafter, referred to as Patent Document 1).
The cell sorting apparatus includes a cell sorting chip that includes a micro flow channel, for example. This apparatus measures, when a fluid including cells flows through predetermined flow channels in the chip, a complex impedance and a complex permittivity among the flow channels and sorts the cells based on the measurement result. The chip includes a signal detection electrode (measurement portion) for measuring a complex impedance and a complex permittivity of cells and detecting signals. The chip also includes as a cell sorting means, on a downstream side of the signal detection electrode, an operation electrode (electric field application portion) having a predetermined shape, that is provided for forming a DC or AC electric field for imparting an appropriate dielectrophoretic force to the cells (see, for example, paragraphs (0025), (0028), etc. in specification of Patent Document 1).